Guest: Dr. David Lawrence. Topic: The planet Mercury & the NASA Messenger Mission. Please direct all comments & questions regarding Space Show programs/guest(s) to the Space Show blog, https://thespaceshow.wordpress.com. Comments & questions should be relevant to the specific Space Show program. Written Transcripts of Space Show programs are a violation of our copyright & are not permitted without prior written consent, even if for your own use. We do not permit the commercial use of Space Show programs or any part thereof, nor do we permit editing, YouTube clips, or clips placed on other private channels & websites. Space Show programs can be quoted, but the quote must be cited or referenced using the proper citation format. Contact The Space Show for further information. We welcomed Dr. David Lawrence to the program to discuss the planet Mercury & the NASA Messenger Mission’s latest finding. For more information, visit the Messenger websites, http://www.nasa.gov/mission_pages/messenger/main/index.html & http://messenger.jhuapl.edu. We started our discussion by describing the Mercury & the Messenger mission. For example, it took over six years to get to Mercury because of the difficulty in slowing the spacecraft down given the close proximity to the sun. Dr. Lawrence explained this process to us & the Venus, Mercury, & Earth flyby program used by the spacecraft to orbit around Mercury. We talked about the spacecraft health, the instruments on board & the problem with the gamma ray spectrometer which worked for about 9,000 hours on an expected life of 8,000 hours. However, data from this instrument is still being analyzed & will be for some time to come. Other instruments on Messenger are fine & the spacecraft has a life expectancy to 2015. Our guest explained mission nominal life & the process for mission extensions with additional NASA funding. We talked about funding issues for Messenger & other planetary missions in light of NASA budget issues & the overall U.S. economy. Dr. Lawrence told us how the missions compete for extension & additional funding, plus the requirements they must meet to be extended. Listeners wanted to know about the application of Messenger & Mercury science to Earth & other solar system missions, our Moon, a NEO, even Mars. Other listeners wanted to know Mercury’s distances from the sun & Earth, as well as more about possible tectonic activity on Mercury. We discussed basic chemical elements found on Mercury as well as volatile elements.

In our second segment, Dr. Lawrence was asked to identify the biggest surprise so far which he said had to do with the composition of the planet & volatile elements with high concentrations of sulfur & sodium, among others. A listener asked about Mercury radiation levels & another listener wanted to know how Mercury crater’s got their names. Dr. Lawrence then took us through the crater naming process which you can also read about on the Messenger websites. We talked about Messenger’s discovery of Hollows (see, http://science.nasa.gov/science-news/science-at-nasa/2011/24oct_sleepyhollows). One listener asked our guest how one gets on a science team like Messenger. Dr. Lawrence explained the paths to joining these teams. Mercury’s high density came up & our guest talked about most all of the iron on the planet being concentrated in its core. We also talked about data analysis, archives, embargos, & availability. Our guest directed us to the NASA Planetary Portal System for more information. Near the end, we talked about the NASA Discovery Program & other successful Discovery missions including Dawn.

Please post your comments/questions on The Space Show blog. You can email Dr. Lawrence through me or the APL Messenger website.